1. Field of the Invention
The present invention relates to a process for preparing an alkyl-substituted aromatic hydrocarbon. More particularly, the present invention relates to a process for preparing an alkyl-substituted aromatic hydrocarbon by reacting an alkylaromatic hydrocarbon having at least one hydrogen atom on an alpha-carbon in said alkyl side chain with an olefin in the presence of a solid base which is obtainable by treating an alumina with at least one compound of an alkaline earth metal in a specific temperature range and successively with at least one compound selected from the group consisting of alkali metals and alkali metal hydride in an inert gas at a specific temperature range, whereby the alpha-position of the alkyl group is alkylated.
2. Description of the Related Art
The alkyl-substituted aromatic hydrocarbons are useful as intermediates in the production of fine chemicals such as agricultural chemicals, medicines and other chemicals and prepared by reacting the alkylaromatic hydrocarbon having the hydrogen atom on the alpha-carbon in the side chain with an olefin in the presence of a base catalyst.
As the preparation process of the alkyl-substituted aromatic hydrocarbon, there are known a process which utilizes a catalyst comprising metal sodium and chlorotoluene and a process which utilizes a catalyst comprising metal sodium supported on potassium carbonate (cf. J. Am. Chem. Soc., 78, 4316 (1956), GB Patent No. 1269280 and Japanese Patent Kokai Publication No. 53229/1986).
However, the conventionally used catalysts have various drawbacks such as insufficient catalytic activities, a low yield of the alkyl-substituted hydrocarbon per unit amount of the catalyst and troublesome separation of the catalysts from the product. Further, the conventional catalysts suffer from such problems in that when they are in contact with the oxygen and/or moisture in the air, they tend to lose their activities or they are ignited.